Abstract:To study the photosynthetic mechanism of submergence resistance in peach rootstocks,we studied the effects of water-logging on photosynthetic characteristics of peach rootstock seedlings ［Maotao (Prunus persica (L.) Batsch.),Shantao (P.davidiana (Carr.) Franch.)］ and Nemaguard with normal water supply as control.The results showed that net photosynthetic rate(Pn),relative water content(RWC),water use efficiency(WUE),transpiration rate(Tr),stomatal conductance(Gs),apparent quantum yield(AQY),carboxylation efficiency(CE) and maximal photosynthetic electron transport rate(Jmax) in leaves were significantly lower than control,but the MDA content was opposite.Nemaguard had higher chlorophyll content under submergence stress in the late experiment period.Meanwhile,decrease amplitude of Pn,RWC,Tr,WUE and Gs of Nemaguard were the lowest among the 3 cultivars,Maotao took second place.The level of water-logging tolerance among the 3 peach rootstock seedlings was Nemaguard>Maotao>Shantao.As response to water-logging,membrane-lipid peroxidation was intensified,the stomatal aperture,water metabolism capacity,photosynthetic electron transport rate and photosynthetic capacity decreased.The chlorophyll biosynthesis of Nemaguard under water-logging enhanced and descending speed of RWC were slower,which led to higher light absorption and water metabolism capacity;Nemaguard had stronger resistance to photoinhibition and photooxidation because of the lowest membrane lipid peroxide level,there for,Nemaguard could keep the highest photosynthetic capacity among the 3 peach rootstock seedlings.